From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752848AbaEVWDx (ORCPT ); Thu, 22 May 2014 18:03:53 -0400 Received: from e23smtp05.au.ibm.com ([202.81.31.147]:56378 "EHLO e23smtp05.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751691AbaEVWDw (ORCPT ); Thu, 22 May 2014 18:03:52 -0400 Message-ID: <537E73FA.60703@linux.vnet.ibm.com> Date: Fri, 23 May 2014 03:32:34 +0530 From: "Srivatsa S. Bhat" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:15.0) Gecko/20120828 Thunderbird/15.0 MIME-Version: 1.0 To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, peterz@infradead.org, rafael.j.wysocki@intel.com, srivatsa.bhat@linux.vnet.ibm.com, toshi.kani@hp.com, ego@linux.vnet.ibm.com, akpm@linux-foundation.org, wangyun@linux.vnet.ibm.com, tglx@linutronix.de, laijs@cn.fujitsu.com, paul.gortmaker@windriver.com CC: tip-bot for Lai Jiangshan , linux-tip-commits@vger.kernel.org Subject: Re: [tip:sched/core] sched: Fix hotplug vs. set_cpus_allowed_ptr() References: <53758B12.8060609@cn.fujitsu.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14052222-1396-0000-0000-000004E5739B Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/22/2014 05:56 PM, tip-bot for Lai Jiangshan wrote: > Commit-ID: 6acbfb96976fc3350e30d964acb1dbbdf876d55e > Gitweb: http://git.kernel.org/tip/6acbfb96976fc3350e30d964acb1dbbdf876d55e > Author: Lai Jiangshan > AuthorDate: Fri, 16 May 2014 11:50:42 +0800 > Committer: Ingo Molnar > CommitDate: Thu, 22 May 2014 10:21:31 +0200 > > sched: Fix hotplug vs. set_cpus_allowed_ptr() > > Lai found that: > > WARNING: CPU: 1 PID: 13 at arch/x86/kernel/smp.c:124 native_smp_send_reschedule+0x2d/0x4b() > ... > migration_cpu_stop+0x1d/0x22 > > was caused by set_cpus_allowed_ptr() assuming that cpu_active_mask is > always a sub-set of cpu_online_mask. > > This isn't true since 5fbd036b552f ("sched: Cleanup cpu_active madness"). > > So set active and online at the same time to avoid this particular > problem. > > Fixes: 5fbd036b552f ("sched: Cleanup cpu_active madness") > Signed-off-by: Lai Jiangshan > Signed-off-by: Peter Zijlstra > Cc: Andrew Morton > Cc: Gautham R. Shenoy > Cc: Linus Torvalds > Cc: Michael wang > Cc: Paul Gortmaker > Cc: Rafael J. Wysocki > Cc: Srivatsa S. Bhat > Cc: Toshi Kani > Link: http://lkml.kernel.org/r/53758B12.8060609@cn.fujitsu.com > Signed-off-by: Ingo Molnar Reviewed-by: Srivatsa S. Bhat Regards, Srivatsa S. Bhat > --- > kernel/cpu.c | 6 ++++-- > kernel/sched/core.c | 1 - > 2 files changed, 4 insertions(+), 3 deletions(-) > > diff --git a/kernel/cpu.c b/kernel/cpu.c > index a9e710e..247979a 100644 > --- a/kernel/cpu.c > +++ b/kernel/cpu.c > @@ -726,10 +726,12 @@ void set_cpu_present(unsigned int cpu, bool present) > > void set_cpu_online(unsigned int cpu, bool online) > { > - if (online) > + if (online) { > cpumask_set_cpu(cpu, to_cpumask(cpu_online_bits)); > - else > + cpumask_set_cpu(cpu, to_cpumask(cpu_active_bits)); > + } else { > cpumask_clear_cpu(cpu, to_cpumask(cpu_online_bits)); > + } > } > > void set_cpu_active(unsigned int cpu, bool active) > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 44e00ab..86f3890 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -5076,7 +5076,6 @@ static int sched_cpu_active(struct notifier_block *nfb, > unsigned long action, void *hcpu) > { > switch (action & ~CPU_TASKS_FROZEN) { > - case CPU_STARTING: > case CPU_DOWN_FAILED: > set_cpu_active((long)hcpu, true); > return NOTIFY_OK; >